This time, Iraq should be broken up

We must go back into Iraq. Then when we leave, we must not leave an Iraq.

In the immediate aftermath of the 2003 invasion, there were two strategic errors. The first was when the Americans took down the US flag in Baghdad. In some American stores the sign says: "If you break it, you own it." We broke Iraq, but then we refused to own it – we refused to raise our flag and say: "It's our responsibility now if your power doesn't work or someone tries to rob you."

The second great error is the one that's really coming to haunt us now: we decided to preserve the territorial integrity and unity of Iraq. Iraq was formed in the early 20th century from three Ottoman provinces: Mosul, Baghdad and Basra. Broadly these areas have continued to have significantly different identities, with only the brutality of Saddam Hussein maintaining order. After we removed him, there was immediately a debate as to whether Iraq should be preserved as one country or, instead, broken into three zones: a Kurdish area in the north, a Shia area in the south and a Sunni area in the centre and the west.

De facto some of this did happen – indeed had already happened shortly after the 1990-91 war. The Kurds established an enclave in the north, protected from the Iraqi military after 1991 by a no-fly zone. After the 2003 war we could have recognised a Kurdish state, and since at that point Iraq would have been being broken up anyway we might naturally have gone on to separate Sunni and Shia areas, also. But we never recognised a Kurdistan because of the Turks.

The Kurds are the largest ethnic minority in Turkey, comprising around a fifth of the population. There was a long-standing struggle between the Turkish government and the Kurdish rebel group(s) – the PKK. The PKK was recognised as a terrorist group not only by Turkey but also by the US, the EU and Nato. Turkey feared that the establishment of a recognised Kurdish homeland in Iraq (and indeed Syria) might spill over into territorial claims in Turkey. So splitting Iraq in the natural way – which would inevitably include a Kurdish-controlled region – did not seem diplomatically feasible. Instead Iraq was notionally preserved as a unity – with disastrous consequences.

In 2013 the Turkey-PKK struggle was deemed ended under the "Solution Process", with all PKK forces withdrawn into northern Iraq. Kurdish forces have achieved international recognition and the gratitude of the people of the regions just south of the Kurdish enclave for their efforts in fighting Islamic State (IS) forces. It seems plausible now that, in due course, if IS forces are defeated, the influence of the Kurdish region will extend to Mosul and Nineveh.

With the Turkey-PKK conflict ended and Kurds sacrificing their soldiers in the struggle against IS, there is a clear mechanism for increasing the local acceptance of what will now surely be a significant military involvement, once again, in Iraq. If we formally recognise Kurdistan and then have the Kurds invite us to assist them in resisting IS, we need not conceive of ourselves as intervening in a civil war – even for the purposes of resisting genocide. Instead, we could simply be helping an ally that is being attacked.

That would still potentially leave a problem in the south, though a decisive engagement of IS forces in the north might break their power sufficiently to allow us to leave open, for the moment, the now awkward question of whether Baghdad will be in a Shia south or a Sunni centre and west state, as well as the other awkward question of whether the Sunni west ends at the current border with Syria or extends into it. To some extent those issues may need to be left fluid and dependent upon the evolution of the conflict. In the first instance, however, if we are willing now, finally, to see Iraq broken up we have the opportunity for ready-made allies who will welcome our assistance in the Kurdish north. We should take it.